To make sure this is the same issue I already know about, can you confirm that when you click on "Add Game..." the file browser opens, you can select a directory, and only after you have selected a directory the cursor remains locked to the 'Add Games..." button?

I and others have reproduced such an issue, but not consistently (most of the times it worked for me), and what happens is that after selecting a directory the file browser remains open hidden in the background and still locks inputs. I am not sure why it happens, but I made changes to ScummVM back in July to try to fix this and have not reproduced the issue since. So hopefully this will be fixed in version 2.0 that will be released in a few weeks.

So that means the changes I made before the 2.0.0 release did not fix the issue (or at least not completely). The problem I have now is that I have been unable to reproduce this issue since I made those changes, and I am at a loss about the possible cause. There are some anecdotal evidence of this happening with other applications on the internet (for exemple here), but nothing that really helps me pinpoint the root of the issue.

It might be worth opening a ticket on our bug tracker to make sure we do not forget about this issue.